They're waiting for you Gordon, at the Black Mesa Website, where they now offer the long-awaited first release of the Black Mesa modification to bring the gameplay from Half-Life to the Source engine (thanks ochentay4). Here's word from the wiki:

Utilizing the Source engine, Black Mesa will reintroduce the player as Doctor Gordon Freeman, along with the original cast of memorable characters and environments seen in Half-Life. Black Mesa was built and founded on the basis that Half-Life: Source didn't fully live up to the potential of a Source engine port of Half-Life. As such, Black Mesa was founded to fully reconstruct the Half-Life universe utilizing Source to its fullest potential in terms of art detail, level sizes and code features. It should be noted that the project is being built from the ground up and is not a simple port of Half Life maps and models into the Source Engine. The idea is to remake the storyline used in Half Life into a new polished Source Engine version with new models, maps, soundtrack, voice acting and textures.

I really want to play it but if I'm going to play an updated version of a classic like Half -Life I want to play the whole thing. However I shudder to think how long it may take them to complete it considering how long it took to get this much out. Hopefully they can finish it faster.

I watched my daughter playing the opening levels and I am struck with just how professional the mod looks. I started tracking this mod the day its page went up on moddb many moons ago; it still feels a bit surreal to see it played given how long ago I wrote it off.

“The greatness of a nation and its moral progress can be judged by the way its animals are treated.” - Mahatma Gandhi